A wiper device provided at the front window of a construction machine generally has a wiper motor arranged in a cab. The output shaft of the wiper motor is connected to the wiper located outside the cab through a through hole formed at the cab wall.
For example, Japanese Patent Laying-Open No. 2010-100122 (PTL 1) discloses a wiper device provided at the front window of a vehicle. The wiper device has a wiper motor arranged inside the vehicle compartment. An output shaft of the wiper motor passes through a through hole formed at the cowl top section to be connected to a wiper member outside the vehicle compartment. Furthermore, a serration section having a diameter becoming smaller towards the tip is provided at the leading end of the output shaft. The wiper member is fixed to the serration section.